Obesity is a major health problem in developed countries. In the United States, the complications of obesity affect nearly one in five individuals at an annual cost of approximately $40 billion. Except for rare pathological conditions, weight gain is directly correlated to overeating.
Noninvasive methods for reducing weight include either increasing metabolic activity to burn calories or reducing caloric intake, either by modifying behavior or with pharmacological intervention to reduce the desire to eat. Other methods include surgery to reduce the stomach's volume, banding to limit the size of the stoma, and intragastric devices that reduce the desire to eat by occupying space in the stomach.
Intragastric volume-occupying devices provide the patient a feeling of satiety after having eaten only small amounts of food. Thus, the caloric intake is diminished while the subject is satisfied with a feeling of fullness. Currently available volume-occupying devices have many shortcomings. For example, complex gastrotomy procedures are required to insert some devices.
Clinical use of intragastric balloons has been ongoing for several years, and its success in the treatment of certain individuals with morbid obesity is well accepted. Volume-occupying devices for use in obesity reduction were developed in the late 1970's and early 1980's. These early designs had multiple complications that caused them not to gain widespread acceptance at the time. Newer designs were developed in the late 1980's, and have led to their wider acceptance in European clinics.
U.S. Pat. No. 4,133,315 discloses an apparatus for reducing obesity comprising an inflatable, elastomeric bag and tube combination. According to the '315 patent, the bag can be inserted into the patient's stomach by swallowing. The end of the attached tube distal to the bag remains in the patient's mouth. A second tube is snaked through the nasal cavity and into the patient's mouth. The tube ends located in the patient's mouth are connected to form a continuous tube for fluid communication through the patient's nose to the bag. Alternatively, the bag can be implanted by a gastronomy procedure. The bag is inflated through the tube to a desired degree before the patient eats so that the desire for food is reduced. After the patient has eaten, the bag is deflated. As taught by the '315 patent, the tube extends out of the patient's nose or abdominal cavity throughout the course of treatment.
U.S. Pat. Nos. 5,259,399, 5,234,454 and 6,454,785 disclose intragastric volume-occupying devices for weight control that must be implanted surgically.
U.S. Pat. Nos. 4,416,267; 4,485,805; 4,607,618; 4,694,827, 4,723,547; 4,739,758; 4,899,747 and European Patent No. 246,999 relate to intragastric, volume-occupying devices for weight control that can be inserted endoscopically. Of these, U.S. Pat. Nos. 4,416,267; 4,694,827; 4,739,758 and 4,899,747 relate to balloons whose surface is contoured in a certain way to achieve a desired end. In the '267 and '747 patents, the balloon is torus-shaped with a flared central opening to facilitate passage of solids and liquids through the stomach cavity. The balloon of the '827 patent has a plurality of smooth-surfaced convex protrusions. The protrusions reduce the amount of surface area which contacts the stomach wall, thereby reducing the deleterious effects resulting from excessive contact with the gastric mucosa. The protrusions also define channels between the balloon and stomach wall through which solids and liquids may pass. The balloon of the '758 patent has blisters on its periphery that prevent it from seating tightly against the cardia or pylorus.
The balloons of the '747 and '827 patents are inserted by pushing the deflated balloon and releasably attached tubing down a gastric tube. The '547 patent discloses a specially adapted insertion catheter for positioning its balloon. In the '758 patent, the filler tube effects insertion of the balloon. In U.S. Pat. No. 4,485,805, the balloon is inserted into a finger cot that is attached by string to the end of a conventional gastric tube that is inserted down the patient's throat. The balloon of the EP '999 patent is inserted using a gastroscope with integral forceps.
In the '267, '827, '758, '747, '805 and EP '999 patents, the balloon is inflated with a fluid from a tube extending down from the patient's mouth. In these patents, the balloon also is provided with a self-sealing hole ('827), injection site ('267, '747), self-sealing fill valve ('805), self-closing valve (EP '999) or duck-billed valve ('758). The '547 patent uses an elongated thick plug and the balloon is filled by inserting a needle attached to an air source through the plug.
U.S. Pat. No. 4,607,618 describes a collapsible appliance formed of semi-rigid skeleton members joined to form a collapsible hollow structure. The appliance is not inflatable. It is endoscopically inserted into the stomach using an especially adapted bougie having an ejector rod to release the collapsed appliance. Once released, the appliance returns to its greater relaxed size and shape.
None of the foregoing patents discloses a free-floating, intragastric, volume-occupying device that can be inserted into the stomach simply by the patient swallowing it and letting peristalsis deliver it into the stomach in the same manner that food is delivered.
U.S. Pat. No. 5,129,915 relates to an intragastric balloon that is intended to be swallowed and that inflates automatically under the effect of temperature. The '915 patent discusses three ways that an intragastric balloon might be inflated by a change in temperature. A composition comprising a solid acid and non-toxic carbonate or bicarbonate is separated from water by a coating of chocolate, cocoa paste or cocoa butter that melts at body temperature. Alternatively, citric acid and an alkaline bicarbonate coated with non-toxic vegetable or animal fat melting at body temperature and which placed in the presence of water, would produce the same result. Lastly, the solid acid and non-toxic carbonate or bicarbonate are isolated from water by an isolation pouch of low-strength synthetic material which it will suffice to break immediately before swallowing the bladder. Breaking the isolation pouches causes the acid, carbonate or bicarbonate and water to mix and the balloon to begin to expand immediately. A drawback of thermal triggering of inflation as suggested by the '915 patent is that it does not afford the degree of control and reproducibility of the timing of inflation that is desirable and necessary in a safe self-inflating intragastric balloon.
After swallowing, food and oral medicaments reach a patient's stomach in under a minute. Food is retained in the stomach on average from one to three hours. However, the residence time is highly variable and dependent upon such factors as the fasting or fed state of the patient. Inflation of a self-inflating intragastric balloon must be timed to avoid premature inflation in the esophagus that could lead to an esophageal obstruction or belated inflation that could lead to intestinal obstruction.
There remains a need for a free-floating intragastric balloon device that can be delivered to the stomach by conventional oral administration and that controllably inflates after an approximately predetermined delay time period.